1. Field of the Invention
The present invention relates to a method of separating diacetoxybutene. More particularly, it relates to a method separating diacetoxybutene from a reaction product resulting from the reaction of butadiene, acetic acid and molecular oxygen.
2. Description of the Prior Art
Diacetoxybutene is an important starting material for producing butanediol which is an important solvent and raw material for various industrial chemicals. Various methods of producing diacetoxybutene have been proposed. A typical method has been the reaction of butadiene, acetic acid and oxygen or an oxygen-containing gas in the presence of a palladium-type catalyst. It is necessary to separate diacetoxybutene from the reaction mixture resulting from this acetoxylation reaction. However, since both the unreacted starting material and the object compound, diacetoxybutene, have unsaturated radicals, polymerization of these compounds occurs quite readily when using separation treatments. Product yield is therefore decreased and operation problems result. The inventors have studied various methods of separating diacetoxybutenes from the reaction mixture of the acetoxylation reaction. As a result, it has been discovered that diacetoxybutenes are easily decomposed or polymerized at higher than a certain specific temperature but are relatively stable at lower than a certain temperature.